refrigeration and air conditioning MCQs – Page 4

Practise focused refrigeration and air conditioning questions with marked answers for exam preparation and subject revision.

refrigeration and air conditioning Mcqs

61. The domestic refrigerator uses following type of compressor ____________________?
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A. axial

B. none of the above

C. piston type reciprocating

D. centrifugal

E. miniature sealed unit

62. Super heating in a refrigeration cycle __________________?
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A. decreases COP

B. COP remains unaltered

C. unpredictable

D. other factors decide COP

E. increases COP

63. The condensing pressure due to the presence of non-condensable gases, as compared to that actually required for condensing temperatures without non-condensable gases ____________________ ?
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A. may be higher or lower depending upon the nature of non-condensable gases

B. will remain unaffected

C. will be higher

D. unpredictable

E. will be lower

64. Cooling water is required for following equipment in ammonia absorption plant__________________?
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A. evaporator

B. absorber

C. condenser and absorber

D. condenser, absorber and separator (rectifier)

E. condenser

65. One ton of the refrigeration is_________________?
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A. the standard unit used in refrigeration problems

B. the refrigeration effect to produce 1 ton of ice in 1 hour time

C. the cooling effect produced by melting 1 ton of ice

D. the refrigeration effect to produce 1 ton of ice at NTP conditions

E. the refrigeration effect to freeze 1 ton of water at 0C into ice at 0C in 24 hours

66. Domestic refrigerator working on vapour compression cycle uses the following type of expansion device____________________?
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A. electrically operated throttling valve

B. capillary tube

C. expansion valve.

D. manually operated valve

E. thermostatic valve

67. Under-cooling in a refrigeration cycle_________________?
0

A. COP remains unaltered

B. decreases COF

C. increases COP

D. other factors decide COP

E. unperdictable

68. In vapor compression refrigeration system, refrigerant occurs as liquid between_________________?
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A. compressor and evaporator

B. none of the above

C. compressor and condenser

D. expansion valve and evaporator

E. condenser and expansion valve

69. The COP of a vapor compression plant in comparison to vapor absorption plant is ________________?
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A. same

B. unpredictable

C. more/less depending on size of plant

D. less

E. more

70. The moisture in a refrigerant is removed by___________________?
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A. expansion valve

B. driers

C. dehumidifier

D. evaporator

E. safety relief valve

71. The coefficient of performance is the ratio of the refrigerant effect to the_________________?
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A. none of the above

B. enthalpy increase in compressor

C. all of the above

D. work done by compressor

E. heat of compression

72. In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to___________________?
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A. detect liquid in vapour

B. increase refrigeration effect

C. collect liquid refrigerant and prevent it from going to compressor

D. superheat the vapour

E. collect vapours

73. The refrigerant for a refrigerator should have ___________________?
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A. high sensible heat

B. high total heat

C. high latent heat

D. low sensible heat

E. low latent heat

74. Reducing suction pressure in refrigeration cycle_________________?
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A. lowers evaporation temperature

B. lowers compressor capacity because vapour is lighter

C. increases power required per ton of refrigeration

D. all of the above

E. reduces weight displaced by piston

75. Critical pressure of a liquid is the pressure_________________?
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A. above which liquid becomes vapour

B. at which all the three phases exist together

C. above which liquid becomes solid

D. above which liquid becomes gas

E. above which liquid will remain liquid

76. Freon group of refrigerants are___________________?
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A. non-toxic and inflammable

B. inflammable

C. toxic

D. non-toxic and non-inflammable

E. non-inflammable and toxic

77. The vapor pressure of refrigerant should be_________________?
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A. could be anything

B. lower than atmospheric pressure

C. higher than atmospheric pressure

D. none of the above

E. equal to atmospheric pressure

78. Mass flow ratio of NH3 in comparison to Freon-12 for same refrigeration load and same temperature limits is of the order of___________________?
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A. 1:01

B. 9:01

C. 1 : 9

D. 1:03

E. 3:01

79. Where does the lowest temperature occur in a vapour compression cycle ?
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A. condenser

B. evaporator

C. receiver

D. expansion valve

E. compressor

80. In a refrigeration system, heat absorbed in comparison to heat rejected is_________________?
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A. more

B. less for small capacity and more for high capacity

C. less

D. more for small capacity and less for high capacity

E. same

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